The genetic constitution of gametes is finally decided at the anaphase-I after which each cell receives half the chromosome number, i.e., from ' ' in parent cell changes to ' ' in daughter cells. During this phase, the two homologue of each chromosome pair separate and move toward opposite poles drawn by microtubule of the spindle apparatus.
These are separated further by anaphase-II, wherein sister chromatids of each chromosome separate and move toward opposite poles. It cannot be metaphase-I or metaphase-II because during these stages, the chromosomes or chromatids, merely arrange themselves at the metaphasic plate.

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